The overall objectives of this project are to elucidate how certain myogenic factors, specifically gastrointestinal slow waves and intercellular coupling, function to coordinate the activities of visceral smooth muscle. Our method of approach will be to study changes in some of the properties of slow waves and electrical coupling induced by certain hormones and physical factors. Specifically, we plan to study: (1) The effects of estrogen, progesterone, pregnancy and parturition on electrical coupling, measured as junctional impedance of the myometrium and also gastrointestinal muscle. (2) The mode of gastrointestinal slow wave propagation, both naturally occurring and electrically driven, in intact gastrointestinal muscle and isolated longitudinal muscle. (3) The electrical activity and electrical properties of isolated mammalian visceral smooth muscle cells.